BEIJING (AP) — A flash flood swept through a construction site in the northwestern Chinese province of Qinghai, killing at least 21 workers, state media reported Wednesday. Three workers are still missing.

Rescuers are still searching for those unaccounted for in Tuesday’s disaster in Wulan county, the official Xinhua News Agency said. Seven injured people were sent to hospitals, it said.

The remote region lies amid high mountains 2,500 kilometers (1,500 miles) west of Beijing, where flash floods are a frequent threat to residents and adventurers drawn by the towering peaks.

Elsewhere in China, heavy flooding in the extreme south and northeast has left more than 200 dead or missing in recent days.

Flooding and landslides in southern China have been chiefly caused by rains brought by last week’s Typhoon Utor. Another storm was bearing down on Taiwan and expected to arrive on mainland China sometime Thursday.